Other Chlorinated Organic Compounds and Dioxin

The success of DDT in 1940s and 1950s led to a development of aU kinds of chlorine-containing organic compounds for pesticides, herbicides, and disinfectants. Many of them were introduced as commercial products, and used widely. Some of those compounds are shown in Fig. 16.1 along with DDT. These seven compounds (except t ,p-DDT) are often labeled as dirty seven for their toxic effects. 

PCDD (polychlorinated dibenzo-p-dioxin) TCDD (2,3,7,8-tetrachloro dibengo-diacin) Fig. 16.2 Dioxins 

A book titled Our Stolen Future appeared in 1996. The authors Theo Colbom, Dianne Dumanoski, and John Peterson Myers argued that some chemical substances dispersed into the environment have gotten into human bodies and disrupted the endocrine (hormonal) system of the humans (and other animals). They built their thesis based on a number of scattered data. 

For example, a Danish reproductive scientist, Niels Skakkebaek started to observe sperm abnormalities as well as a drop in the sperm count (the number of sperms in a unit volume). He also noticed that the number of patients with testicular cancer tripled in Denmark between 1940s and 1980s. He and his coworkers checked literatures available at the time and found to their surprise that the average human 

This second example suggests that even a very small quantity of an environmental contaminant might be effective in disrupting the reproductive system. This (and of course, a lot other reports) led to a thesis that such an effect is very likely due to the effect on endocrine systems, as they are based on low level of specific chemicals, i.e., hormones. 

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